Unit 7 - Our Biosphere
Climatic Influences
Terrestrial Biomes
Aquatic Ecosystems
Vocabulary Unit 7 (22)
Aphotic zone
Benthic zone
Biome
Climate
Coniferous
Deciduous
El Nino
Estivation
Estuary
Flood plain
Greenhouse effect
Greenhouse gas
Hibernation
Littoral zone
Limnetic zone
Permafrost
Photic zone
Thermohaline circulation
Topography
Upwelling
Weather
Wetland
Unit 7A
Climatic Influences
Chps. 16.1 & 16.2
Weather
• “Weather”……………what is it?
• What is happening in the atmosphere at
a particular place at a particular
moment
• “The temperature is 82º with winds
coming out of the southwest.”
Climate
• “Climate” is the average weather in an
area over a long period of time
• “Summer temperatures usually reach into
the low 90’s with scattered afternoon
thunderstorms.”
• Factors: temperature, humidity, winds,
precipitations
• These factors determine what types of
organisms live in a region
What factors determine
climate?
1.
2.
3.
4.
5.
Latitude
Atmospheric circulation patterns
Ocean circulation patterns
Local geography
Seasonal changes in climate
1. Latitude
• The distance from the equator
measured in degrees north and south of
the equator
• Determines the amount of solar energy
an area receives
• Vertical concentrated rays v.s. oblique
dispersed rays
2. Atmospheric
circulation patterns
• Cold air sinks, warm air rises
• Warm air can hold more water vapor
than cold air
• Cooler air causes water vapor to
condense into liquid
• Solar energy warms the air closest to
the Earth’s surface, causing it to rise
• There’s more………………
• Rising air is replaced by cooler air
flowing in from further north and south
• Resulting in a circulation cell
• Cool air over the equator cannot sink
and is forced away, sinking at about
30º latitude
• This causes warmer dry air, and is why
most of the Earth’s deserts are at this
latitude
3. Ocean circulation
patterns
• Water holds heat
• Currents redistribute warm and cool
masses of water
• Coastal areas have a more moderate
climate with more moisture
• U.S. temperate rain forest
4. Local geography
• Temperatures fall with increase in
elevation (air cools as it rises)
• Mountains influence distribution of
precipitation
• Warming air draws up moisture from the
surface of the Earth
• Cooling air releases its moisture
• Rain on the west side, deserts in the “rain
shadow” of the mountains
5. Seasonal changes
• Seasons result from the Earth’s orbit
around the sun and the tilt of the Earth
relative to its path
• Four seasons occur, except in the
Tropics where it remains constant
Greenhouse Effect
• What is it?
• Light energy goes through the
atmosphere and heats the Earth
• As heat rises, some of it escapes back
into space
• The rest of the heat is trapped by gases
in the troposphere, which then warm
the air
Greenhouse Gases
• The gases that trap and radiate heat
back to the Earth
• The major greenhouse gases:
• Water vapor, carbon dioxide,
chlorofluorocarbons (CFCs), methane,
and nitrous oxide
Atmospheric Carbon
Dioxide Fluctuation:
• Seasonal – lower in the summer as plants
use it up; higher in the winter as dying
plants release carbon
• Why?
• Burning fossil fuels releases stored carbon
• Burning living plants releases carbon
• Oceans absorb 50 times more CO2 than air
Global warming
• Increasing levels of greenhouse gases
increases the average temperature of the
Earth
• This produces a warmer climate
• Oceans absorb more heat, increasing
hurricanes and typhoons
• Disrupted weather patterns could alter
agriculture
• Sea levels will rise due to melting glaciers
How to slow down global
warming:
• Use less fossil fuels, reducing the
amount of carbon dioxide released into
the atmosphere
• Preserve existing forests
• Plant more trees
How oceans affect climate
• By transporting heat and absorbing
CO2
• Thermohaline circulation: warmer,
less salty water moves along the
surface; colder, saltier, denser water
moves deep
• Colder, saltier water at the poles sinks
while warmer, less salty from the
equator moves to take the place of the
cooler water
El Niño & La Niña
• Interactions between the oceans & the
atmosphere that affect climate
• Change in air pressure, wind patterns, ocean
temperature & ocean circulation in the
Pacific Ocean
• Normally, winds and currents move warm
water west along the equator
• El Niño: winds weaken & warm water flows
back towards S. America, rains in S. Cali.
• La Niña: opposite, cooler water in the
eastern Pacific Ocean
El Niño &
La Niña
Unit 7 B
Terrestrial Biomes
Chapter 6
Biomes
•“Biomes” - areas that have
distinctive climates and
organisms
•Biomes are named according
to their plant life
•Climate is the main
determinant
1. Tropical Rain Forests
• Occur in a belt around the Earth
near the equator
• Always humid and warm
• Get about 100” of rain a year &
strong sunlight year-round
• Ideal climate for growing plants
• Soil is thin and poor
Plant adaptations
Tropical Rain Forests
• Plants grow in layers
• Dense canopy at top absorbs most
of the sunlight
• Little light reaches the
understory
• Epiphytes: plants that grow on
other plants instead of soil
Animal adaptations
Tropical Rain Forests
• Great diversity of animals,
each adapted to exploit a
specific resource
• Camouflage is common
Threats to Rain Forests
Decreased from covering 20%
to 7% of the Earth
Destroyed by logging or
clearing for ranches
Animals and native people are
becoming extinct
• The canopy receives over 95% of available
sunlight, leaving very little for vegetation
below. How would this affect
photosynthesis at the lower levels?
• Where would you find the greatest amount
of biomass in the rain forest?
• At what level of the rain forest would you
most likely find herbivores? Decomposers?
• How is a rain forest like the ocean?
• Because of the dense shade on the forest
floor, a rain forest is NOT a jungle. Why?
Countries that have
Tropical Rain Forests
•
•
•
•
•
•
•
•
Brazil
Ecuador
Thailand
Cambodia
Venezuela
Columbia
Guatemala
Costa Rica
2. Tropical Dry Forest
• Rainfall is highly seasonal; wet & dry seasons
span about ½ year each
• India, southern N. American, Central
America, S. America, SE Asia
• Wet season rains are very heavy
• Organisms must adapt to fluctuations in
precipitation and temperature
• Most trees are deciduous; roots deeper than
tropical rain forest; some store water
• Animals migrate, estivate
3. Temperate Rain Forests
• Occur in North & South America,
Australia, & New Zealand
• Pacific northwest is only one in U.S.
• Cool, humid forests pervaded by
moisture and abundant moss
• High rainfall & moderate
temperatures provide ideal climate
for lots of plant growth
• Coniferous (cone-bearing) trees like
cedars, spruces, hemlocks, firs
4. Temperate Deciduous
Forests
• Trees drop their broad, flat leaves
each fall
• Generally occur between 30 and 50
north latitude
• Seasonal variations can be extreme
• Only 4 - 6 months of growing season
• Moist (30-100” rainfall per year)
• Soil is rich and deep
Animal Adaptations
Temperate Deciduous Forests
• Numerous habitats,
generally organized by
layers
• Birds migrate, animals
become inactive, insects
enter a state of very low
metabolic activity
5. Boreal Forests/Taiga
• The northern coniferous forest
• Terrain is rough and forest floor is
sparsely vegetated
• Winters are long and extremely
cold
• Frost-free growing season is short,
but enhanced by constant daylight
• Most of precipitation falls as snow
Plant adaptations - Boreal
• Conifers do not shed their needles,
whose narrow shape & waxy coat helps
the conifer to retain water
• Conifer’s cone shape helps it shed snow,
thick bark protects it from frost, &
shallow root system uses water
immediately
• Needles are acidic, deterring competitive
plant growth
• Soil forms slowly because climate &
acidity hinder decomposition
Animal adaptations
Boreal Forests
• Lakes and swamps attract birds
in summer….lots of insects!
• Fur color changes
• Underground burrows for
insulation
Countries that have
Boreal Forests
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Norway
Sweden
Finland
Russia
Canada
Alaska (U.S.)
Germany
Northern China
Grassland, Deserts, &
Tundra
Characterized by less rainfall and
less diversity of species
1. Tropical Savannas
• Found in the tropics, inland, near
the equator
• Contain the greatest # of
grazing animals on Earth
• Too little rain for many trees to
grow
• Grass fires are common
Plant adaptations
Tropical Savannas
• Large underground root
systems that survive fire &
drought
• Vertical leaves of grasses
help conserve water
• Thorns deter hungry
herbivores
Animal adaptations
Tropical Savannas
• Herbivores migrate to
follow rains
• Competition avoided by
eating different height
vegetation.
2. Temperate Grasslands
Prairies, Steppes & Pampas
• Low rainfall, periodic droughts, and
high temperatures
• The most fertile soil of any biome
• Found in the interiors of continents
where there is too little rainfall for
trees to grow
• Fire is common due to low rainfall,
high temperatures
Location of Grasslands:
• Prairies: N. America
• Steppes: Russia & Ukraine
• Pampas: S. America
Plant adaptations
Temperate Grasslands
• Grasses are perennials with
dense matted root systems
that help them survive
drought and fire and hold
soil
• Amount of rainfall
determines type of grasses
Animal adaptations
Temperate Grasslands
• Burrowing animals
protected from fires & the
elements
Threats to Temperate
Grasslands
• Overgrazing decreases
regeneration & increases soil
erosion
• Grain crops cannot hold the
soil in place, increasing soil
erosion
3. Deserts
• Driest places on Earth
• Defined as areas that receive
less than 10” annual rainfall
• Dryness hinders decay, so soil is
very poor in organic matter
• Few nutrients are washed out, so
soil is high in minerals
Plant adaptations - Deserts
• Getting and conserving water
• Thick fleshy stems, waxy leaves,
spines for protection
• Shallow wide root systems
• “Drought-resistance” – a survival
strategy to live through the
worst desert conditions
• New plants germinate, grow and
bloom very rapidly
Animal adaptations - Desert
• Dry, scaly skin that prevents
water loss
• “Estivating” – burying
themselves in the ground and
sleeping through the dry season
• Most animals are partially
nocturnal
Threats to Deserts
• Residential development
spurs water rights battles
• Off-road vehicles destroy
vegetation/habitat
4. Tundra
• Definition: a biome without trees,
where grasses and tough shrubs
grow in the frozen soil
• “Permafrost” – permanently
frozen soil, impermeable
• Top few inches of soil thaws in
the summer, causing bogs and
swamps to form as water cannot
penetrate the permafrost
Tundra Plant Adaptations
• Mosses and lichens grow without
soil
• Most plants are tiny and short to
keep them out of the wind and
help in absorbing heat from the
soil
• Dwarf forms have adapted
• Brief summers cause rapid
growth and flowering
Tundra Animal Adaptations
• Migratory birds feed on
swamp/bog insects
• Winter camouflage and
underground burrows
• Well insulated fur and
feathers
Threats to the Tundra
• One of the most fragile
biomes on Earth as food
chains are simple and easily
disrupted
• Extreme conditions cause
land to be easily damaged
and slow to recover
• How many major land biomes are on Earth?
• 7
• Describe the distribution of tropical
rainforests.
• Tropical rainforests are found mostly
between the Tropic of Capricorn and the
Tropic of Cancer
• In what country is ice found as a land
biome?
• Greenland
• Describe the distribution of tundra.
• Tundra is found near the Arctic Circle.
• Which three terrestrial biomes can be
found in large areas of the U.S.?
• Temperate grasslands, temperate
forests, and deserts
• Which continent was once practically
covered in temperate forest?
• Europe
Unit 7 C
Aquatic Ecosystems
Chapter 6
Freshwater Ecosystems
“Freshwater” – water that
contains relatively little
dissolved salt
Life depends on depth of the
water, how fast the water moves
and the amount of mineral
nutrients, sunlight and oxygen
1. Lakes and Ponds
• “littoral zone” – the nutrient
rich area along the shore where
sunlight reaches the bottom
• Phytoplankton, zooplankton
and the organisms that feed on
them live in open water where
there is enough sunlight for
photosynthesis
• “benthic zone” – the bottom of a body
of water which is inhabited by
decomposers, insect larvae and clams
• “eutrophic lake” – a lake with a large
amount of plant nutrients
• As plants and algae numbers increase,
so do the number of bacteria growing.
The bacteria use up the oxygen
dissolved in the lake’s waters
What does the benthic
zone have lots of?
C.R.A.P.
• Carbon
• Rich
• Anaerobic
• Product
Plant and Animal
Adaptations
• Floating plants in deeper waters
• Trapped air in the hairs of some
insects
• Whiskers on catfish help sense
food in the dark
Questions
• What process allows an abundance of life
near the surface of a lake?
• Photosynthesis
• If light never penetrates into the deepest of
lakes, how can life exist?
• Bacteria and decomposers feed on debris
from above
• In the picture, the benthic zone is larger than
the littoral zone. Is this always the case?
• Usually it is.
• Explain how the benthic zone can be
located in areas where light does and does
not reach.
• It is primarily located at the bottom, but
some lakes are shallow enough that light
penetrates to the bottom
• Which of the following bodies of water
would contain a benthic zone where light
does not reach: Lake Erie, Lake Michigan,
Mississippi River, Walden Pond, Great Salt
Lake, Lake Okeechobee?
• They all do
2. Wetlands
• Areas of land that are covered with
water for at least part of the year
• “marshes” – contain non-woody
plants
• “swamps” – contain woody plants
and shrubs
• Many fish use freshwater wetlands
for breeding and feeding
• Wetlands are home for
migrating and native wildlife
• Wetland vegetation traps
carbon, decreasing atmospheric
carbon dioxide and global
warming
• Wetlands remove pollutants
from the water and control
flooding
Marshes
• Shallow water, rich bottom
sediment
• Nesting birds attracted to
marshes
• “brackish marshes” – slightly
saline water
• “tidal marshes” – contain
saltier water
• Everglades is the largest
freshwater marsh in the U.S.
Swamps
• Occur on flat,
Cypress Swamp
poorly drained land
• Often located near
streams
• Dominated by
shrubs or watertolerant trees
Values of Wetlands
• Purifiers of wastewater and
absorbers of hazardous flood
waters
• Important habitats for wildlife
• Wetlands are threatened by
development today
3. Rivers
• Usually originate from snowmelt in
mountains
• Headwaters are cold and highly
oxygenated
• Varies with changes in land and
climate through which it flows
• Slows down with deeper, less
oxygenated water as it gets further
from its origin
River Plant and Animal
Adaptations
• Churning headwaters support
mosses which can anchor to rocks
• Fish’s streamlined bodies present
less resistance to strong currents
• Long, thin-leafed plants near the
faster moving headwaters
Threats to Rivers
• Industries and people use rivers
as waste dumps
• Run-offs from land put in
pesticides and other poisons
• Dam-building alters flow and
destroys fish habitats
Marine Ecosystems
• Ocean environment
• Lack of water is not a problem
• Temperature and amount of
sunlight and nutrients are the
determining factors
1. Estuaries
• An ecosystem in which fresh
water from rivers mixes with
salt water from the ocean
• The waters trap nutrients, which
fall to the bottom
• Very nutrient-rich ecosystem
Plant & Animal Adaptations
• Light and rich nutrients support
large populations of plants,
phytoplankton and zooplankton
• All organisms are adapted to
tolerate variations in salinity ***
• Find lots of filter feeders in this
biome
Threats to Estuaries
• Large ports often result in
dumped wastes and small oil
leaks/spillage
• Fill-ins from building sites
• Sediments and run-offs
2. Coral Reefs
• Limestone islands in the sea built by
coral animals
• One of the most diverse ecosystems
• Only in salt water with enough
sunlight for photosynthesis
• Found in shallow tropical seas
• Cover less than .2% of the ocean floor,
yet it contains 25% of its species
Animal
Adaptations
• Parrotfish have
beaklike teeth to
scrape algae and
corals off
• Anemonefish have
slime resistant to sea
anemone poison
Threats to Coral Reefs
• Temperature, salinity changes and
pollutants decrease limestone production
• Overfishing upsets the balance of a reef’s
ecosystem
• Oil spills, sewage, and pesticide & silt
runoff
• Muddy or polluted water prohibits sun from
reaching the algae
• Coral grow very slowly
• Dropped anchors, tourism
3. The Ocean
• Covers nearly 75% of the Earth’s surface
• Plants grow only where there are nutrients
and enough light for photosynthesis
• Much of the life is concentrated in
shallow water around the edges of the
continents
• Open ocean is one of the least productive
of all ecosystems
Plant Adaptations
• Flowering plants are absent
from oceans except around the
edges (no pollinators)
• Phytoplankton provides food
for herbivores
• Buoyancy devices prevent
sinkage into deep water
Animal adaptations
• Zooplankton are the smallest herbivores
• Many creatures evolved sleek, taper
shapes for moving through dense water
• Sharks have oily livers to float, fish have
gas-filled swim bladders
• Sound carries very well over long
distances, so creatures use it for
communication
Threat to the Oceans
• Pollution increasing, including
radioactive wastes, industrial
pollution and plant nutrient runoff
• Overfishing and nets reduce
reproduction
4. Polar Ecosystems
• Ice-covered polar caps at both
Poles
• Considered marine ecosystems
as nearly all the food is
provided by phytoplankton in
the ocean
The Arctic
• The Arctic Ocean is relatively
shallow, so rich in nutrients
from the surrounding land
masses
• Rich diversity of fish
The Antarctic
• Only continent never colonized
by humans
• Fish feed on plankton
Threat to Polar Ecosystems
• Reserves of minerals (like oil)
would cause disruption of
untouched ecosystems is
extracted
• Increase in tourism threatens
wildlife with garbage
Test Review
• Know the vocabulary terms
• Know the distinctive characteristics of
all the major ecosystems around the
world, including savannas, grassland,
tropical rain forests, open ocean,
deserts, tundra, taiga, rivers, estuaries,
and temperate deciduous forests
• Know how animals and plants adapt for
survival in some of the harshest biomes
• Know how human activities threaten some
of the more fragile biomes
• Be prepared to give examples of countries
that contain biomes often found between
24º N latitude and 24º S latitude, as well as
between 55º and 70º N latitude
• Be prepared to write about one particular
biome in detail
References
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Pearson Environmental Science
Environmental Science – Holt
Environmental Science – Enger & Smith
Florida Wildlife magazine
National Geographic magazine
Google images